I seem to be running into this ‘blindness’ all the time.
Zero is not a number.
It is only a concept.
Before it was ‘invented’ thinking could not proceed.
After it was ‘invented’ some people apparently failed to grasp the full implications of what was said, just used it as a very convenient tool and moved on.
The facts are, you cannot, except by convention, use zero in any equation and convey true accuracy. You cannot, again except by convention, truly represent it in any numbering system, including Unary.
It is a representation of a blank space, a ‘ ‘ which means just that but in a scientific sense. A circular wrapper around the blank space which otherwise is very hard to see on the page.